rear end

i was wondering the difference from a 10 bolt to a 12 bolt. and if you were to switch to 373 or 411 gears would you just switch the housing, gears, or would the entire axle need to be changed? thanks

The entire axle assembly must be changed. The "12" and "10" describe the number of bolts holding the ring gear to the carrier. While this is also true of the cover on the housing, not ALL axles with 12 bolts holding the cover on are "12 bolts". We have one here right now, from a '70 GTO, with 12 bolts holding the cover, and only 10 on the ring gear.
If you're talking about the "big" 10 bolt (8.5" ring gear), there's not a lot of improvement in strength by going to the 12-bolt. Actually, the "big" 10-bolt is a 12-bolt with only 10 holes drilled in it (some variation, but effectively). If you're speaking of the little 10-bolt (8.2 or 7.5), and you have significant power and/or torque, get a 12-bolt...

thanks, so far you seem to be the only one on here who knows something other than what car beats what in a race. however, should i be looking for a 12 bolt and not really be concerned about what gearing it has or look for the 373/411 in the 12 bolt?

What about horsepower limits on the 10 VS 12 bolt rearend? Big 10 VS little 10 bolt?

you want to stay away from the 8.2 ten bolt those are extremely weak.

A 8.5 ten bolt built right can handle a lot of power.